Undefined String for Mongoose.connect() on deploy, but works locally

Question

I'm trying to deploy a node app to Render, but keep getting this error message: MongooseError: The uri parameter to openUri() must be a string, got "undefined". Make sure the first parameter to mongoose.connect() or mongoose.createConnection() is a string.

After searching on here for a while and trying different things, I'm still getting the same result and I don't really know why. My connection works locally, but when I try to deploy it fails.

const express = require('express');
const mongoose = require('mongoose');
require('dotenv').config({path:__dirname+'/.env'});
const cors = require('cors')

const quizRoutes = require('./router/quiz');
const articleRoutes = require('./router/article');

const app = express(); 

//middleware
app.use(express.json());

app.use(cors());


app.use(function (req, res, next) {
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
    res.setHeader('Access-Control-Allow-Credentials', true);
    next();
    });


app.use('/quiz', quizRoutes);
app.use('/articles', articleRoutes);

mongoose.connect(process.env.MONGO_URI)
    .then(() => {
        app.listen(process.env.PORT, () => {
            console.log(process.env)
            console.log('Port', process.env.PORT);
        })
    })
    .catch((error) => {
        console.log(error);
    })

PORT=4000
MONGO_URI="mongodb+srv://personalinfo.lahdouv.mongodb.net/?retryWrites=true&w=majority"

Changed Mongo_URI for obvious reasons, but that is the code I'm working with.

I tried changing the .env config, putting the URI in quotes, and trying to make sure that the .env file was being linked correctly. Locally, I used console.log to make sure, and it still works. Not sure where to go from here.

Any help is greatly appreciated and thank you very much for your time.

Answer 1

Instead of using env file you can try this. There is an extended option in render to add environment variable before the apps starts to be deployed . select advanced option and you will see an option to add environment variable . add variable save and deploy